In 2020, ‘Sodammi’ was developed as a sweetpotato with a slightly moist texture, excellent palatability, and appearance. It was derived from a cross between ‘Hogammi’ (IT327288), which has a slightly moist texture and excellent palatability, and ‘Kyushu No. 121’ (IT309496), which has a yellow flesh and good appearance. The storage roots of ‘Sodammi’ have a purple-red skin, yellow flesh, and an ovate shape. ‘Sodammi’ storage roots exhibit a slightly moist texture and are more tender than those of the check variety ‘Jinhongmi’. The sweetness of steamed storage roots of ‘Sodammi’ was 19.1, which was 24.8% higher than that of ‘Jinhongmi’. Palatability of steamed storage of ‘Sodammi’ was better than that of ‘Jinhongmi’. The marketable storage root yield of ‘Sodammi’ was 19.6 MT/ha during the normal season culture. ‘Sodammi’ is moderately resistant to Fusarium wilt and root-knot nematodes. ‘Sodammi’ had very good storability, as there was almost no decay rate and no internal cavitation during long-term storage. Cultivation of the ‘Sodammi’ variety is expected to expand considerably, as it has characteristics favored by consumers, farmers, and distributors due to its excellent palatability, appearance, and storability (Registration No. 8789).

In 2019, ‘Bodeuremi’ was developed as a high-yielding sweetpotato variety with good palatability. It was derived from a cross between ‘MI2006-58-02’ with high yield and ‘Beniharuka’ (IT309504) with good palatability. The storage roots of ‘Bodeuremi’ have a red skin, light orange flesh, and an ovate shape. When steamed, ‘Bodeuremi’ storage roots exhibit a moist texture and are more tender than those of the check variety ‘Pungwonmi’. The sugar content of steamed ‘Bodeuremi’ storage roots was 33.4 mg/100 g dw, which was 6.0% higher than that of ‘Pungwonmi’. The marketable yield of ‘Bodeuremi’ storage roots was 30.3 MT/ha in the early season culture, which was 4.5% higher than that of ‘Pungwonmi’ with high yield in the early season culture. ‘Bodeuremi’ is resistant to root-knot nematode and moderately resistant to Fusarium wilt. ‘Bodeuremi’ is expected to contribute to increased income of sweetpotato growers as it has high cultivation stability and can be shipped at a time when the market price is high owing to its high yield in the early cultivation.

In order to select sweetpotato varieties with excellent tip characteristics, we investigated the appearance, yield, and functional compounds in 32 domestic sweetpotato varieties. During the cultivation period, the total production of sweetpotato tips among the different variety ranged from 1,780 to 9,923 g/m², with that of the Gogeonmi variety being the highest. The lutein content among varieties ranged from 21.7 to 47.0 mg/100 g and was highest in the Juhwangmi variety, whereas the ß-carotene content ranged from 25.5 to 183.4 mg/100 g and was highest in the Hayanmi variety. The total polyphenol content ranged from 30.7 to 74.4 mg CAE/g, and it was high in the Pungwonmi, Daeyumi, and Dahomi varieties at 74.4, 73.8, and 72.9 mg CAE/g, respectively, whereas the DPPH radical scavenging activity of tips ranged from 88.6% to 91.6%, with Gogeonmi and Healthymi showing the highest value of 91.6%. ABTS radical scavenging activity was found to be lowest in the Yeonjami variety at 86%, whereas the remaining 31 varieties showed values in excess of 96%. ABTS radical scavenging activity showed a high positive correlation with total polyphenol content. On the basis of these analyses, we identified Juhwangmi with high lutein content, Hayanmi with high beta-carotene content and high yield, and Gogeonmi with high DPPH radical scavenging activity and high yield, as being suitable varieties for tip cultivation. We anticipate that these sweetpotato varieties with excellent tip characteristics will be used as parents for the breeding of varieties for vegetable use.

AbstractIn 2016, ‘Jinyulmi’ was developed as a sweetpotato variety with good palatability and high marketable storage root yield. It was derived from a cross between ‘Sinchunmi’ and ‘Jeonmi’. ‘Sinchunmi’ is small, with an average storage root weight of 141 g and an average number of marketable storage roots of 3.4. ‘Jeonmi’ has a high storage root yield of 26.2 MT/ha and intermediate steamed storage root texture. The storage roots of ‘Jinyulmi’ are elliptical and have red skin and yellow flesh. ‘Jinyulmi’ is resistant to Fusarium wilt and moderately resistant to root-knot nematode. The steamed storage root texture of ‘Jinyulmi’ is intermediate and more tender than that of check variety ‘Yulmi’. The sweetness of ‘Jinyulmi’ steamed storage roots was 13.1, which was 12.9% higher than that of ‘Yulmi’. ‘Jinyulmi’ steamed storage roots are also more palatable than those of ‘Yulmi’. The marketable storage roots yield of ‘Jinyulmi’ was 24.2 MT/ha in the early season culture, which was 26.0% higher than that of ‘Yulmi’. Its average marketable storage root weight was 137 g in the normal season culture, which was lower than that of ‘Yulmi’, but the number of marketable storage roots per plant was 3.6, which was higher than that of ‘Yulmi’. The marketable storage root yield of ‘Jinyulmi’ was 28.6 MT/ha in the normal season culture, which was 19.7% higher than that of ‘Yulmi’. ‘Jinyulmi’ is, therefore, suitable for both early and normal season cultures (Registration No. 7053).

‘Danjami’ was developed in 2015 as a purple-fleshed sweetpotato variety with excellent palatability. It was derived from a cross between ‘Yeonjami’ with purple flesh and ‘Yeonhwangmi’ with good palatability. The storage roots of this variety are elliptical with purple skin, and light purple flesh. It is moderately resistant to fusarium wilt and resistant to root-knot nematode. The texture of the steamed storage root of ‘Danjami’ is slightly moist and more tender than that of ‘Sinjami’. Soluble solid content of steamed storage roots of ‘Danjami’ was 31.3 °Brix, which was 20.8% higher than that of ‘Sinjami’. The palatability of steamed storage roots of ‘Danjami’ was better than that of ‘Sinjami’. The anthocyanin content of storage roots of ‘Danjami’ was 55.1 mg/100g dry weight. Total polyphenol content and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity did not differ from that of ‘Sinjami’. The number of marketable storage roots per plant and the average weight of marketable storage root was 2.8 and 136 g under the normal and late-season culture in ‘Danjami’, respectively. The marketable storage root yield of ‘Danjami’ was 21.5 MT/ha under the normal and late-season culture, which was 78.8% of that of ‘Sinjami’. The yield of marketable storage root over 50 g of ‘Danjami’ was 15.3 MT/ha under the early-season culture, which was 28.8% lower than that under the normal and late-season culture. ‘Danjami’ was more suitable for the normal and late-season culture than for the early-season culture (Registration No. 6465).

‘Hogammi’ was developed as a sweetpotato variety with β-carotene content and excellent palatability in 2015. It was derived by crossing ‘AB95007-2’, which has good shape and storage root yield, and ‘Annoimo’, which has light orange flesh and good palatability. ‘Hogammi’ had storage roots with long elliptical shape, red skin, and light orange flesh. The texture of the steamed storage root of ‘Hogammi’ was intermediate or slightly moist, and it was more tender than that of ‘Yulmi’. The soluble solid content of the steamed storage roots of ‘Hogammi’ was 29.7 °Brix, which was 10.8% higher than that of ‘Yulmi’. The palatability of the steamed storage roots of ‘Hogammi’ was better than that of ‘Yulmi’. The β-carotene content of the storage roots of ‘Hogammi’ was 9.8 mg/100 g dry weight. ‘Hogammi’ was moderately resistant to Fusarium wilt and root-knot nematode. In ‘Hogammi’, the number of marketable storage roots per plant and the average weight of marketable storage root were 3.4 and 133 g under culture in the normal season, respectively. The marketable storage root yield of ‘Hogammi’ was 24.1 MT/ha under culture in the normal season, which was 4% higher than that of ‘Yulmi’. The yield of marketable storage root over 50 g of ‘Hogammi’ was 14.5 MT/ha under culture in the early season, which was 39.8% lower than that under culture in the normal season. ‘Hogammi’ was more suitable for culture in the normal season (Registration No. 6466).

‘Yeseumi’, a new sweetpotato variety resistant to fusarium wilt, was developed for table use by Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), Rural Development Administration (RDA) in 2013. ‘Yeseumi’ was derived from the cross between ‘Mokpo34’ and ‘Singeonmi’ resistant to fusarium wilt in 2005. The seedling and line selections were conducted from 2006 to 2008. Preliminary and advanced yield trials were carried out from 2009 to 2010. The regional yield trials were performed at five locations from 2011 to 2013. ‘Yeseumi’ has three-lobed leaf, and its leaves, stems, petioles, and nodes are green. Storage root of ‘Yeseumi’ has an elliptical shape, red skin, and light orange flesh. ‘Yeseumi’ was highly resistant to fusarium wilt and susceptible to root-knot nematode. Dry matter content was 25.4%, and texture of steamed storage root was intermediate. Total sugar contents of raw and steamed storage root of ‘Yeseumi’ were higher than those of ‘Yulmi’. β-carotene content of ‘Yeseumi’ was 15.7 mg/100 g DW. Yield of marketable storage root over 50 g of ‘Yeseumi’ was 32.5 MT/ha under the early season culture, which was 97% higher than that of ‘Yulmi’. The number of marketable storage roots per plant was 2.8 and the average weight of marketable storage root was 143 g under the normal and late season culture. Marketable storage root yield of ‘Yeseumi’ was 23.9 MT/ha under the normal and late season culture, which was 42% higher than that of ‘Yulmi’. (Registration No. 5848).

‘Pungwonmi’, a new sweetpotato variety, was developed for table use by Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), RDA in 2014. This variety was derived from the cross between ‘Benisatsuma’ and ‘Luby3074’ in 2006. The seedling and line selections were performed from 2007 to 2009, and preliminary and advanced yield trials were carried out from 2010 to 2011. The regional yield trials were conducted at five locations from 2012 to 2014, and it was named as ‘Pungwonmi’. This variety has cordate leaf shape, and its leaves, stems, nodes, and petioles are green. Storage root of ‘Pungwonmi’ has an elliptical shape, red skin, and light orange flesh. ‘Pungwonmi’ was moderately resistant to fusarium wilt, and resistant to root-knot nematode. Dry matter content was 31.2%, and texture of steamed storage root was intermediate. Total sugar content of raw and steamed storage roots of ‘Pungwonmi’ was higher than that of ‘Yulmi’. β-carotene content of ‘Pungwonmi’ was 9.1 mg/100g DW. Yield of marketable storage root over 50 g of ‘Pungwonmi’ was 24.3 MT/ha under the early season culture, which was 46% higher than that of ‘Yulmi’. The number of marketable storage roots per plant was 2.8 and the average weight of marketable storage root was 156 g under the optimal and late season culture. Marketable storage root yield of ‘Pungwonmi’ was 24.1 MT/ha under the optimum and late season culture, which was 26% higher than that of ‘Yulmi’. (Registration No. 6428).

Geonpungmi is a new sweetpotato variety developed by Bioenergy Crop Research lnstitute in the National Institute of Crop Science (NICS) at RDA for table use in 2008. This variety was selected from the cross between Mokpo34 and Southern Queen. Two parents, Mokpo34 and Southern Queen, were crossed in 2002. Selection of elite line was performed for 2 years from 2003 to 2004. Preliminary and advanced yield trials were carried out from 2004 to 2005. The regional yield trials were conducted at six locations from 2006 to 2008. Geonpungmi has cordate leaf, greenish purple vine and petiole, elliptic storage root, dark purple skin and yellow flesh color of storage root. This variety is resistant to fusarium wilt and nematode. The starch value and total sugar content were 25.8% and 5.82%, respectively. Pasting temperature of starch in Geonpungmi was 74.7°C, and the retrogradation process is earlier than Yulmi. The average yield of storage root is 19.8 ton/ha in the regional yield trials, which is 3% lower than that of Yulmi. The number of marketable storage roots per plant was 2.6 and the average weight of one storage root was 154 g.

‘Geonhwangmi’, a new sweetpotato variety, was developed for table use by Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), and RDA in 2013. This variety was derived from the cross between ‘Singeonmi’ and ‘Mokpo34’ in 2005. The seedling and line selections were performed from 2006 to 2008, preliminary and advanced yield trials were carried out from 2009 to 2010. The regional yield trials were conducted at five locations from 2011 to 2013, and it was named as ‘Geonhwangmi’. This variety has five-lobed leaf, and its leaves, stems, and petioles are green. Storage root of ‘Geonhwangmi’ has an elliptical shape, red skin, and light orange flesh. ‘Geonhwangmi’ was moderately resistant to fusarium wilt, and resistant to root-knot nematode. Dry matter content was 29.4%, and texture of steamed storage root was intermediate. Sucrose content of steamed storage root of ‘Geonhwangmi’ was higher than that of ‘Yulmi’, and steamed storage root palatability of ‘Geonhwangmi’ was better than that of ‘Yulmi’. β-carotene content of ‘Geonhwangmi’ was 3.4 mg/100g DW, which was 7.8% of ‘Juhwangmi’. Yield of marketable storage root over 50 g of ‘Geonhwangmi’ was 23.0 MT/ha under the early seasonal cultivation, which was 39% higher than that of ‘Yulmi’. The number of marketable storage roots per plant was 2.6 and the average weight of marketable storage root was 151 g under the optimal and late seasonal cultivation. Marketable storage root yield of ‘Geonhwangmi’ was 24.2 MT/ha under the optimum and late seasonal cultivation, which was 45% higher than that of ‘Yulmi’. (Registration No. 5853).

‘Dahomi’, a new sweetpotato variety, was developed for table use by the sweetpotato breeding team of Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), RDA in 2012. This variety was derived from the cross between ‘Muan4’ and ‘Jinhongmi’ in 2005. The seedling and line selections were performed from 2007 to 2008, preliminary and advanced yield trials were carried out from 2009 to 2010, and the regional yield trials was conducted at five locations from 2011 to 2012 and it was named as ‘Dahomi’. This variety has three or five lobes leaf, green leaf, stem, and petiole. Storage root of ‘Dahomi’ was elliptic, red skin, light orange flesh. This variety is resistant to fusarium wilt, but susceptible to root-knot nematode. Texture of steamed storage root was intermediate, and degree Brix of steamed storage root was 24.8 °Brix. The total sugar content of raw and steamed storage root was 9.7, 32.0/100 dry weight (g), respectively, which was higher than that of ‘Yulmi. Storage root yield of ‘Dahomi’ was 26.3 MT/ha under the early seasonal cultivation, which was 52% higher than that of ‘Yulmi’. Storage root yield of ‘Dahomi’ was 21.9 MT/ha under the optimum and late seasonal cultivation, which was 35% higher than that of ‘Yulmi’. The number of storage roots over 50 g per plant was 2.8 and the average weight of storage root was 138 g under the optimum and late seasonal cultivation.